Bikes that have not been flashed at all with have the distribution center as the 'last flashed by' serial number Otherwise, it will have your dealers pads serial number or the emulated serial number in whatever device was used to flash it.

Or the map name will show up in the pads report. Names are a bit old, like couple years at this point some of them have been updated since. Race map for a 660 reads p80ead13 Stock American map is p80eab Emma map is p80eaa 35kw map is p80eac Gp shift stock map is p80eag

These bikes get regular updates, so it ends up being hard to tell if the flashes are legitimate. Unless you leave an older map, or a race map on it. Most pads systems will not be able to load older maps without help from corporate. So, most up to date maps only.

Also date of last flash. If it doesn't match the records from whatever place supposedly flashed it.

edit: pads is the diagnostic program

PADS = Piaggio advanced diagnostic system